Help on building an enclosure

[EddyCurrent]

Painting is ok but any Ground points will need cleaning back to metal. Regards Star grounding then you don't have to take all grounds back to the case. You can just use a Bus bar and run all to this point, then take Ground wire from this to Case.

Yes I forgot to specifically mention that earth points must be free of paint, you need good contact to bare metal, star washers are a good idea as they bite into the metal.

Other things I would incorparate is a Fan to pull air out and filtered vent to let air be pulled thru. Two fans could be used but not required.

I've found it's best to blow air in rather than suck it out. If you suck air out then crap can bypass the filter and find it's way in through gaps, holes, etc. because the air pressure inside the box is lower than outside.
We used to apply the same idea to complete electrical switch rooms.